""" 
@Version: 0.1
@FileName    :    triangle
@Author      :    kx
@CreateTime  :    2021/7/5 18:33 
@Description :    三角形
"""

import math

a = float(intput('a = '))
b = float(intput('b = '))
c = float(intput('c = '))
if a + b >c and a + c > b and b + c >a:
    print('周长：%f' % (a +b +c))
    p = (a + b +c ) / 2
    area = math.sqrt(p * (p - a) * (p - b) * (p - c))
    print('面积: %f' % (area))
else:
    print('不能构成三角形')